How to Get Entei in Sapphire

Choose Bulbasaur as a starter in "Pokemon FireRed" or "LeafGreen." If you pick another starter, you won't be able to obtain Entei. Challenge and defeat the Pokemon League once you obtain the eight gym badges from the Kanto gym leaders.

Walk in the long grass of any route in Kanto. Eventually, Entei will appear. Within a few turns, it will flee from the fight. Find a Level 50 Pokemon that knows Mean Look, like Haunter. Make sure you have a Water- or Rock-type Pokemon in your party.

Check your map. The flashing dot will represent Entei. Go to any city in Kanto. Walk out of the city and onto a route with grass. The Entei will go to a different route each time you arrive in a new location. Enter and leave the city until Entei is in the same location as you.

Put the Pokemon that knows Mean Look as your first Pokemon. Look for Entei in the long grass. Once you find the Legendary Dog, use Mean Look immediately, so it won't be able to flee. Fight the Entei with Water- and Rock-type moves. Throw Ultra Balls at the Pokemon once it has low hit points.

Go to One Island and talk to Celio. Complete the quest for the Ruby and the Sapphire. Give the gems to Celio to unlock an option to trade from "FireRed" or "LeafGreen" to "Sapphire."

Start "Pokemon Sapphire" in one Game Boy Advance (GBA) and "Pokemon FireRed" or "LeafGreen" in another GBA. Connect the hand-held devices with a GBA link cable. Ascend the stairs to the second floor of the Pokemon Center in both games. The woman behind the centrally located counter will take you to a room where you can trade the Entei.